Examine source code of SpoilerGuard

{
  "manifest_version": 2,
  "name": "SpoilerGuard",
  "version": "1.1.1",
  "description": "Hides posts containing specified words in facebook posts to protect you from spoilers.",
  "options_page": "options.html",
  "browser_action": {
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "*://www.facebook.com/*"
      ],
      "js": [
        "hidespoilers.js"
      ],
      "css": [
        "style.css"
      ]
    }
  ],
  "permissions": [
    "storage"
  ],
  "applications": {
    "gecko": {
      "id": "spoiler-guard@example.com",
      "strict_min_version": "53.0"
    }
  },
  "icons": {
    "48": "images/icon_48.png",
    "128": "images/icon_128.png"
  }
}